I have prpoposed and with my colleagues have demonstrated enhancement of selective drug delivery to target aeas by combining local hyperthermia with encapsulation of the drug in properly engineered liposomes. Near their liquid crystalline transition temperature (Tc), liposomes become highly permeable to water soluble contents. The basic strategy has been, and will continue to be, to design liposomes with Tc a few degrees above the physiological in a range attainable by mild hyperthermia. As we have already shown on passing through the heated area in circulation, the liposomes release their contents at a greater rate than elsewhere thus developing a higher local concentration of drug in the area of interest. The current studies include investigation of drug release and uptake by hyperthermia from drug-laden liposomes in in vivo tumors (JM-9 and CA 755) and in heated normal tissue.